Field of the Invention
This invention relates generally to exercise machines. More specifically, the invention relates to supplemental weight stacks for exercise machines.
Description of Related Art
Exercise machines are commonplace at many gyms and homes because machines have some advantages over free weight exercises. One advantage is that exercise machines allow users to perform exercises they may not be able to perform with free weights. Another advantage is the machines are often safer than free weights. However, one of the major disadvantages of exercise machines is that the weights increase at a predetermined increment. For example, if each weight in the weight stack is 20 pounds, a user could not increase the weight by 5, 10, or 15 pounds. Likewise, if the weights are in 10 pound increments, a user could not increase the weight by 2.5, 5, or 7.5 pounds.
U.S. Pat. No. 7,413,532 to Monsrud et al. presents one possible solution to this problem by including supplemental weights stacked on top of one another where each weight has a corresponding vertical leg. The user rotates a dial and a spring-loaded pin engages one of the vertical legs. The added weight depends on which vertical leg is selected.
U.S. Pat. No. 7,252,627 to Carter also discloses a supplemental weight stack with vertically stacked weights. This weight stack operates via a wheel with pins spaced unequally from the center. As the wheel is rotated, the pins engage the supplemental weights. The pin furthest from the center corresponds to the highest weight.
The prior art relies on vertically stacked weights and spring-loaded engagement mechanisms. These can lead to safety issues and less stability. Therefore, the present invention is drawn to a more stable, safer supplemental weight stack.